Background Cardiac procedures often require blood transfusion due to surgical bleeding or coagulopathy. Thrombelastography (TEG) is used to direct transfusion in cardiothoracic surgery in our institution. The study aims to quantify the effect of TEG on transfusion requirements and surgical bleeding in isolated valve replacements/repairs.MethodsPatients who underwent isolated valve repair/replacement before and after implementation of TEG were retrospectively analyzed. Variables including transfusion rates, mean use of blood products, and mediastinal re-exploration rates were compared by study period in minimally invasive and open approach cases using t-test and chi square analysis.Results In total, 278 patients were identified. In the perioperative period, use of plasma (p<0.0001) and cryoprecipitate (p=0.009) were significantly reduced in minimally invasive cases and all cases combined. Only use of plasma was reduced in open approach cases. The proportion of patients exposed to transfusion in the perioperative period was significantly reduced (p=0.03). The overall rate of re-operation due to bleeding decreased significantly (9.8% vs 2.6%, p=0.01). The reduction in need for re-exploration was more apparent in minimally invasive cases than in open cases, which occurred in 8.8% of patients prior to using TEG compared to 1.2% after TEG was used to guide management of bleeding.ConclusionsTEG-directed management of blood product administration during isolated valve surgery significantly reduced the use of plasma and cryoprecipitate, with fewer patients receiving allogenic blood products perioperatively. Re-operation rates were reduced nearly four-fold. The use of TEG to monitor perioperative hemostasis significantly impacted transfusions and reoperations for bleeding in this cohort.